Four-stroke-cycle internal-combustion engine



FESMAL.

FOUR-STROKE CYCLE INTERNAL COMBUSTION ENGINE.

' APPLICATION FILED Aus.'12. 1921.

1,417,694. Patented M y 30, 1922.

UNITED STATES PATENT OFFICE.

FIRMIN SMAIJ, OF COUTI-IUIN, BELGIUM.

FOUR-STROKE-GYCLE INTERNAL-COMBUSTION ENGINE.

Application filed August12, 1921. Serial No. 491,858.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.) i

To all whom it may concern:

Be 1t known that I, FIRMIN SMAL, a sub"- ject of the King of the Belgians, residing at Couthuin, Belgium, have invented a certain Improvement Relating to Four-Stroke- Cycle Internal-Combustion Engines (for which I have filed applications in France Sept. 10, 1917, and in England Oct. 2, 1917, No. 113,242), of which the following is a specification.

This invention relates to improvements in four-stroke-cycle internal combustion engines the valves of which are operated by a cam shaft and to engines comprising one or more pairs of parallel cylinders, each pair working on the same crank. The invention relates more particularly to engines intended for us on motor propelled vehicles.

The invention is characterized by a valve cam shaft having two sets of cams, so adapted that one or the other set may be brought into action to operate the valves in such a way as to produce in each pair of cylinders in the one case an alternate explosion in the two cylinders every two' strokes, or in the other case a simultaneous explosion in the two cylinders, every four strokes.

The advantage of this arrangement will be appreciated when it is considered that in automobile practice, it is well known that the multiplication of the cylinders of an en gine results in a more regular and's-moother running on a level road but that on the other hand, in a coast, the multiplication of cylinders is often a disadvantage because it diminishes the potential of the engine, that is the maximum power developed by each explosion upon the crank which receives it.

lVit-h the above arrangement it is possible, with four cylinders, for example, to give four single explosions when running on a level road, and when in a coast, two double explosions, every four strokes.

The accompanying drawings illustrate diagrammatically and by way of example, the valve cam shaft, with two sets of cams, for an engine having one pair of cylinders actlng on one crank.

F'gure 1 shows the first set of cams;

An inspection of this figure will indicate double explosion every four strokes.

As regards the mechanical control of the arrangement, this may be effected by the axial movement of the shaft fitted, with a fixed key or feather, or by movement of the cams on the shaft, or by any other suitable system of control.

I claim: The improvement relating to four-stroke internal combustion engines having valves" controlled by a cam shaft and comprising one or more pairs of parallel cylinders each pair worklng on the one crank, characterlzed by a valve cam shaft having two sets of.

cams, each of which may be brought into action at will andseparately to operate. in such a" manner the valves of cylinders as to produce, upon each correeach pair of sponding crank, by the first set an alternate explosion in the cylinders of each pair, for every two strokes, and by the second set, a simultaneous explosion in the two cylinders every four. strokes, substantially as and for the purpose hereinbefore set forth.

In testimony thereofI signed hereunto my" name in the presence of two subscribing witnesses. i

FIRMIN SMAL.

lVitnesses SEVERINE HAUSEUNE, E. HEEDEN'I'. 

